Transformer construction



Aug. 13, 1940. ms. EDWARDS 2,211,690

TRANSFORMER CONSTRUCTION Filed Aug. 20, 1937 2 Sheets-Sheet 1 y A? INVENTOR V iQ ober S. Edwards ATTORN EY Aug. 13, 1940. R. s. EDWARDS TRANSFORMER CONSTRUCTION Filed Aug. 20. 1937 2 Sheets-Sheet 2 v W LZEQIE:

INVENTOR Roberf 15'. Edwards BY I ATTORNEY Patented Aug. 13, 1940 UNITED STATES PATENT OFFICE TRANSFORMER CONSTRUCTION Application August 20, 1937, Serial N0. 160,031

8 Claims.

This invention relates to transformer construction and more particularly to the construction and installation of transformers such as are used principally in building construction where alternating current energy, usually on the order of 110 volts, is to be reduced to a lower voltage, such as a voltage on the order of 15 volts or so, for the operation of various auxiliaries or low voltage devices.

One of the objects of this invention is to provide a transformer construction and installation, particularly of the above-mentioned character, that will be simple, dependable and practical, that will be capable of inexpensive manufacture, and that will be capable of simplicity, ease, and reliability of installation or practical application. Another object is to provide a construction of the above-mentioned character that will be capable, in a practical, dependable and inexpensive manner, of installation under a variety of conditions met with in practice. Another ob- Ject is to provide a transformer construction and mounting therefor capable of flexibility of installation according to whichever of several various practical conditions are met with.

Another object is to provide a transformer construction with eflicient, simple and inexpensive mounting means therefor that will be well adapted to meet certain practical conditions. 30 Another object is to provide a transformer construction with simple and dependable means whereby the transformer may be mounted in various ways depending upon the particular conditions or circumstances such as the type of wiring system, for example, with which the transformer is to become associated. Another object is to provide a transformer construction of the above-mentioned character with efiicient, reliable and secure means whereby it may be quick 40 ly, inexpensively and reliably mounted either openly as on a panel, or in association with a wall or outlet box.

Another object is to provide a transformer construction capable of inexpensive, dependable 45 and rapid association with or mounting in or with respect to a wall or outlet box. Another object is to provide a construction for carrying out the just stated object in such a way that the transformer may at will be associated with such 50 a box or mounted independently thereof or openly, as on a panel or like support. Another object is to carry out the said object in such a way that the transformer may be dependably and inex pensively related to different types or styles of such boxes.

Another object is to provide a casing construction for a transformer of the above-mentioned character that will be simple and inexpensive to manufacture and that will have dependably and inexpensively incorporated therein certain 5 mounting means whereby simplicity and inexpensiveness of manufacture are achieved as well as simplicity and inexpensiveness of mounting and installation brought about. Another object is to provide a sheet metal casing for a transformer of the above-mentioned character capable of interrelation with the transformer per se and so constructed that strong, dependable and inexpensive mounting or supporting means for the transformer construction as an entity are inexpensively provided.

Another object is in general to improve transformer constructions and installations of the above-mentioned character. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of the various possible embodiments of my invention:

Figure 1 is a plan view of the transformer construction;

Figure 2 is a perspective view of the transformer per se;

Figure 3 is a front elevation as seen from the lower end of Figure 1;

Figure 4 is a rear elevation as seen from the upper end of Figure 1, but in Figure l a supporting plate is fragmentarily shown related to the construction;

Figure 5 is a bottom plan view as seen from the under side of Figure 1;

Figure 6 is a partly sectional side elevation as seen from the right in Figure 1;

Figure '7 is a perspective view of an illustrative type or form of wall or outlet box, together with a closure or transformer supporting plate according to certain features of my invention;

Figure 8 is a perspective view of another illustrative type or form of wall or outlet box, 59 with a closure or transformer supporting plate according to certain features of my invention;

Figure 9 is a view as seen along the line 99 of Figure 4 showing, however, only certain of the parts in cross-section, and

Figure 10 is an end elevation as seen from the left in Figure 9.

Similar reference characters refer to similar parts throughout the several views of the drawings.

By way of illustration of several of the more usual requirements or conditions met with in practice and hence as conducive to a readier understanding of certain aspects of the invention, I have indicated at in Figure 6 a flat-surfaced support, such as a panel, switchboard, wall surface, or the like, on which the transformer construction, according to one condition, is to be directly mounted, and in Figures '7 and 8 I have indicated at 2i and 22, respectively, two of the more usual types or shapes of boxes, usually of heavy sheet metal, used in certain types of wiring systems and known by various names, such as wall, or outlet, or conduit boxes and with respect to which the transformer is to be related to have its high voltage side connected to the high voltage circuit or circuits terminating in or passing through the outlet box. -In carrying out the last above-mentioned object, the transformer construction of this invention embodies features making it universally applicable to a variety of practical requirements of which the three just mentioned may be considered to be illustrative.

The transformer construction embodies a transformer per se which, as is shown in Figure 2, may comprise any suitable form of core 23 of any suitable magnetic material, preferably laminated, and it may be of the shell type, having core windows and a central core leg 22 with respect to which the high and low voltage windings, generally indicated by the reference character 25, are related in any usual or suitable manner, it being apparent that the windings project to both sides of the core 23. This transformer per se is encased in a casing made preferably of sheet metal and illustratively and preferably of three sections which in Figures 1 and 6, are generally indicated by the reference characters 26, 21 and 22, and which, furthermore, are constructed so that they may be conveniently and inexpensively formed as by appropriate punch press operations.

Considering the three casing sections, the central section 27 (see also Figures 3 and 4) is shaped generally to envelope the core 23 peripherally while sections 26 and 28 are shaped appropriately to accommodate therein the laterally projecting portions of the windings 25 and the lead wires (not shown) from the high voltage and low voltage coils thereof.

Thus, section 26 may, for example, be made up out of a stamped blank and shaped in any suitable manner to give it a box-like form, open at one end and peripherally flanged; illustratively, therefore, the casing section 26 may have a generally square wall 26 from which extend four wing-like members bent at right angles to the plane of the wall 26 to form end walls 26', 26, 26 and 26, these four wing-like members appropriately abutting as at J or being otherwise suitably joined. These four end walls are,

furthermore, provided with flanges 26 26 26 and 2t) (Figures 4 and 6), these flanges extending in a plane parallel to the plane of the square wall 25* and falling within an area, illustratively substantially square, that matches the lateral area or outline of the transformer core 23 of Figure 2. The flanges, as indicated in Fig= ure 4, form preferably a continuous even though butt-jointed flange peripherally of the 2,21 i,cao

box-like casing section 26 so that the latter may be laid against one of the lateral faces of the core 23 to cover over the windings 2E and to bring this substantially continuous flange face to face against a lateral face of the core 23 and with its peripheral edges in substantial alinement or coincidence with the alined edges of the laminations of the core 23'.

The square wall or face 25 (Figures 1, 4 and 6) carries a terminal block 29 of a suitable insulating material like fiber, secured thereto preferably as by ears 3I stamped out of the face 26 and clamping the block 29 in place; the latter carries suitable connecting devices 32, 23 which, before assembling the casing section 25 to the transformer 23-45, as above described, are connected respectively to the terminals or lead wires (not shown) of the lower voltage section or coil of the winding 25; to the connecting devices 32, 33, thus positioned externally of the ultimate transformer casing, the low voltage circuit may be connected. Illustratively, they are shown in the form of binding screws.

In the preferred embodiment of this invention the ultimate casing structure is provided with a number of mounting means which preferably are formed integrally with the casing construction itself and where the latter is made up of several sections, as in the illustrative embodiment, certain of the mounting means are preferably formed integrally with the casing section 26. To the latter end, I prefer, therefore, to provide the flange 26 (Figures 6 and 4) with preferably two spaced extensions 35, shaped as better appears from Figures 4, 5 and 6, from which it will be seen that the extensions, where integrally formed with the flange 26, extend or are bent outwardly from the latter and thence downwardly, terminating in flat portions apertured as at 36, adapted to rest flatwise against a suitable supporting surface, like that of the member 20, as shown in Figure 6. Where the casing construction is made of sheet metal, such as sheet iron, it is preferred to have the extensions 34, 35 which form in efiect supporting legs or standards, somewhat yieldable or springlike and a suflicient amount of such springiness may be inherent in the sheet iron or sheet metal employed in making up the casing.

In a somewhat similar way, casing section 28 is made up to have a substantially square wall 28 from which four wing-like extensions are bent at right angles to provide the side walls 28 28, 28 and 28 (Figures 3 and 6), again to form a box-like casing portion open at one end, that open end being peripherally flanged as by the flange extensions 28 28 28 and 28, extending in a plane parallel to the plane of the face 28 The resultant peripheral flange, substantially continuous, is adapted to engage face to face the opp0- site lateral face of the transformer core 23 (Figure 2) whose periphery it substantially matches.

The face or wall portion 28 has secured to it in any suitable manner, as by ears 36 and 31, a terminal block 38 of insulating material like fiber to carry suitable connectingmeans whereby the high voltage side of the transformer may be electrically connected; preferably the construction is such as to simply have extending therethrough insulated lead wires as and so (Figures 3 and 6) of suitable length, the inner ends of which, prior to assembling the casing section 28 to the transformer structure of Figure 2, as above described, are connected in any suitable manner to the ter minals or leads of the high voltage section of the winding 25.

Like the flange 2|i of casing section 26 (Figure 4) the casing section 28 (Figure 3) has its flange 2|! provided with extensions 4|, 42 shaped and constructed as was above described with respect to the legs or standards 34, 35.

However, and since, as will later appear, it is desired to provide the transformer construction with a coacting securing or mounting means, and since it is preferred that the latter be integrally formed with the casing construction, I prefer to interrupt the flange 28 (Figure 3) at suitable points, illustratively two, to provide an upstanding portion 28' (see Figures 3 and 6) which is extended to a sufficient extent and beyond and preferably curved over as at 43. Preferably, also, this extension 43 is springy and preferably it is so shaped or bent that normally, as in Figures 3 and 6, its extreme end falls short of contacting the upper wall portion 28 of the casing section 28, thus to provide sufficient range of resilient or yielding movement of the tongue-like extension 43 in a direction toward the wall face 28 Preferably, also, and in a similar way, flange 26 (Figures 4 and 6) is interrupted to provide an upstanding portion 26 that has an extension I43.

Casing section 21 is also preferably of sheet metal and is in general of inverted U-shape, as viewed in Figures 3 and 4, having a horizontal or top portion 21 and two vertical or end portions 21 and 21, peripherally flanged as at F (Figures 3, 4 and 6), the section 21 being proportioned so as to take over and peripherally, on three sides, encase the core 23 (Figure 2), together with the corresponding peripheral flanges of the casing sections 26 and 28, one portion of each of the peripheral flanges F (see Figures 1, 3, 4 and 6) being cut away to permit the members 43 and H3 freely to project therethrough and to be externally exposed (as is better shown in Figure 6). The casing section 21, with its flanges F on both of its edges, thus acts to hold the casing sections assembled to the transformer core 23, and preferably flanges F are appropriately operated upon so as to clamp between them and securely hold the parts that are interposed between them,

namely the peripheral flanges of the two casing sections 26 and 28, and the transformer core 23. Where the latter is laminated, the clamping ac tion thus also aids to bind the laminations together.

The lower ends of the vertical portions 21 and 21 of the central casing section 21 (see Figures 3, 4 and 5) are provided with strap-like extensions 21 and 21 which are, after the abovedescribed assembly, bent or folded inwardly one upon the other and against the lowermost edge of the transformer core 23, as better appears in Figures 3 and 4, thus completing the casing con struction, whence they are secured in overlapping relationship in any suitable manner.

Illustratively, one of these extensions, like extension 21 (Figure 5) may be provided with an aperture 21 and the other member 21 with a tongue 21 that is passed through the aperture 21 pulled up tightly, and then bent over, thus to hold the two parts in the above-described overlapping relationship.

When it becomes necessary to mount the resultant transformer construction, as on the flat face of a suitable support like the member 2|) of Figure 6, the four standards or legs 3435 and 4|42 are rested against the supporting surface and secured thereto as by nails or screws, or the like, as indicated at 48 in Figure 6, the leads 39 and 40 being used to connect thev high voltage windingto an appropriate circuit and the con-' necting devices 32, 33 having connected thereto the conductors (not shown) of the low voltage circuit.

However, when it is desired to relate the transformer to an outlet box like those above-mentioned with respect to Figures 7 and 8, I provide a mounting plate generally indicated in those figures by the reference character P; centrally of the plate P, which is made of a suitable heavy sheet material, preferably sheet metal, and which is appropriately shaped peripherally as indicated to match the shape of the outer box, there is out or stamped out an opening 50 which in outline is geometrically similar but slightly larger than the outline or shape of the casing section 28 but is smaller than the outline of the casing section 21; hence the former may be freely passed into the opening 50 in the plate P, as is better shown in Figures 9 and 10, up to such an extent as will bring the latter, central casing section 21, flush against one face of the plate P.

Referring again to Figures 7 and 8, the opening 50, in one of its edges, is cut out, as at 5|, to an extent appropriate to accommodate the standard-forming means, preferably and illustratively the two extensions 4|, 42 (Figures 1 and 3) which are on the same side of the central casing section 21 as is the latch-like member 43, while another bounding edge of the opening 50, namely that opposite the edge having the cut-outs 5|, is provided with a cut-out 52 (Figures 7 and 8) for coaction with the member 43.

Accordingly, in relating the transformer to the plate P, as above described in connection with Figures 9 and 10, the standard-forming means, namely, the legs or standards 4|, 42 are first passed through the hole 50 in such manner that they ride into and along the cut-outs 5|, 5|, respectively, until the lower left-hand portion of the central casing section 21 (as viewed in Figure 9), comes into abutting relation to the right-hand face of the plate P, a major portion of the casing section 28 with the leads 39, 40 being thereby passed through the aperture 50; in this relationship the curved member 43 abuts against the right-hand upper edge of the cut-out 52, the parts being preferably purposely so proportioned to bring about this action. If, thereupon, the transformer construction and the plate P are then squeezed together as by the fingers of the hands, the member 43 yields and this action may also be accompanied, if desired, by a yielding or slight bowing of the legs or standards 4|, 42, thus causing the apex or crest of the member 43, the latter being bowed downwardly, to pass through the cut-out 52 and by the inherent springiness of the parts, preferably of the member 43 and if desired also of the members 4| 42, the apex or crest of the member 43 snaps upwardly to the left of the plate P, as viewed in Figure 9, and as shown also in Figure 10, securely and strongly holding the transformer construction assembled to the plate P.

The plate P is then mounted in closing relationship to the outlet or wall box and in such case with the lead wires 39 and 40 and the casing section 28 extending inwardly into the box, the lead wires 39, 40 having, of course, been first connected to the circuit conductors that extend into the box. Exposed outwardly of the box, that is, to the right of the closure plate P, as seen in Figure 9, is a portion of the transformer construction with the terminal block 29 and its connecting devices to which the conductors of the low voltage circuit are connected.

The mounting of the transformer construction in the plate P is strong and secure. The members 43 and 4l42, acting like spring-like tongues, are under compression because of the proportioning of the parts 52 and 5I-5l, respectively, of the plate P, and in tending to expand away from each other (see Figures 9 and 10) exert a strong grip on the plate P but also and preferably, because of their respective preferred shapes and the relatively stiff springiness thereof, they constantly act to draw and hold the transformer construction with the central casing section 21 held snugly against the right-hand face (Figure 9) of the plate P. These spring-like members in effect have cam-like configurations to insure this action and hence each in effect grips the plate P between a crest-like portion of itself and the central casing section 21. Thus, it will be seen that the member 43 (Figure 9) inclines upwardly toward the left and the member 42 has a portion that inclines downwardly toward the left, and as the above-described expansion thereof takes place, they form, to the left of the plate P, portions that are spaced apart farther than the vertical spacing, as viewed in Figures 9 and 10, between the bottoms of the cut-outs through which they respectively pass.

Similar actions and coactions are brought about where, instead of utilizing the members 4l-42 and 43, it is desired to bring the members 34-35 and I43 into coaction with the opposed portions of the aperture 50 in the plate P. In such case, the standard-like members 34, 35 are first passed through the hole 50 so that they ride into and along the cut-outs 5|, 5|, respectively, until the larger casing section 21, acting as a stop, limits 0 such movement, whence the transformer construction is tilted with respect to the plate P to force the resiliently yieldable member I43, with a snap-like action, past the opposed edge or cutout portion 52 of the plate, thus holding the two 5 parts securely together.

Thereby a wide flexibility of application is provided while the preferred identity of construction of the casing sections 26 and 28 simplifies manufacture of the two end casing sections.

50 Furthermore, the plates P, as is usually the case,

are constructed with appropriate screw holes, apertures, slots, or the like, so as to be reversible when applied as closures or covers to their respective outlet boxes; the plate with the transformer already secured thereto .may, therefore, simply be reversed to bring the high voltage end or leads of the transformer construction into the interior of the box.

However, the transformer structure may be removed from the supporting plate P, should that be necessary, and this may be achieved manually without the use of tools by forcing the construction to the right, as viewed in Figure 9, out of the aperture 50; preferably, this demounting is achieved by forcing the upper portion of the transformer structure in a sort of pivoting movement clockwise out of the hole in the plate P so as to cause the member 43 to yield and pass its crest from the left to the right of plate P.

Thus, it will be seen that there has been provided in this invention a transformer construction and installation in which the various objects hereinbefore noted together with many thoroughly practical advantages are successfully achieved. The construction is strong, durable,

dependable, is simple and inexpensive to manufacture, and is simple to manipulate in practice according to the particular requirement met with. From the view-point of manufacturing, substantial savings are effected in that a single style or standard of transformer construction need be tooled-up for and carried in stock while standard plates of varying shapes or configuration need no more than to have a practicable form of aperture or hole stamped therein. The jobber, contractor or electrician need not carry as heavy an inventory for here, also, a single form of transformer construction plus an appropriate supply of the simple and inexpensive varying shapes of plates P suffices to put him in a position to meet a large variety of practical requirements met with in practice.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In apparatus of the character described, in combination, a transformer comprising a casing for housing the transformer core and winding, and a plate member for interconnection with said transformer, said plate member having an aperture therein for receiving therethrough a portion of said casing, said casing being made up of a plurality of sheet metal casing sections comprising two end casing sections having peripheral flanges to rest respectively against two opposed faces of said core for covering over said winding, the portion of said casing receivable into said aperture being one of said end casing sections, and sheet metal means forming a connecting casing section resting alongside opposed edges of said core and having connections with the opposed portions of said peripheral flanges to hold said end casing sections assembled to said core, at least one of said casing sections having integral therewith opposed tongue-like extensions for engaging resiliently opposed edges of said aperture in said plate member at least one of said tonguelike extensions being resiliently yieldable.

2. In apparatus of the character described, in combination, a transformer construction comprising a casing for housing the transformer core and windings, said casing being made of sheet metal and comprising several casing sections having means for securing them together to substantially close over said core and windings, two opposed sections of which have leg-like extensions forming spaced supporting standards which may be used to secure the transformer in position where it is to be mounted on a supporting surface or the like, and additional extensions of resilient tongue-like form, and a supporting plate for said transformer, said plate having an aperture therein to receive a portion of said casing With at least one of said leglike extensions and one of said resilient tonguelike extensions coacting resiliently with said plate to hold said transformer construction assembled thereto.

3. In apparatus of the character described, in combination, a transformer construction comprising a casing for housing a core and its winding and having a main casing portion of larger projected area than the two end casing portions thereof, said casing having at the bottom thereof two supporting means extending oppositely from each other and away from the main casing portion, said supporting means being capable of use for securing said transformer construction to a supporting surface or the like, a plate having an aperture through which an end casing portion may be extended but not large enough to let said main casing portion pass therethrough, one of said supporting 'means being passed through said aperture with said end casing portion and coacting with an edge of said aperture to hold said transformer construction assembled to said plate, and means carried by said casing and brought into coaction with an edge of said aperture in response to completion of movement of said end casing portion through said aperture for coacting with said supporting means in holding said transformer construction assembled to said plate.

4. An iron-core transformer structure of the bell-ringing type comprising a sheet metal casing for housing the transformer core and winding, and a plate-like member for mechanical interconnection with said transformer, said plate member having an aperture therein, into which said transformer structure is receivable, said casing having stop means to limit the extent of passage of said transformer structure into said aperture, said casing having on opposed sides of that portion thereof that enters through said aperture sheet metal tongues to coact with correspondingly opposed portions of the edge wall of said aperture, at least one of said tongues being resilient and substantially cam-shaped for yielding toward the other tongue under the pressure exerted thereon as said casing portion is moved into said plate aperture to the extent permitted by said stop means and acting thereafter to resist removal of said transformer construction from said aperture.

5. In apparatus of the character described, in combination, a transformer structure comprising a casing for housing the transformer core and winding, and a-plate-like member for mechanical interconnection with said transformer, said plate member having an aperture therein, into which said transformer structure is receivable, said casing being made of sheet metal and comprising two end casing sections having peripheral flanges to rest respectively against two opposed side faces of said core for closing over the winding on the latter and means forming a third casing section extending along edge faces of said core with mechanical connection to opposed portions of said peripheral flanges to hold said end casing sections assembled to said core and providing stop means to limit the extent of passage of said transformer structure into said aperture, at least one of said casing sections having opposed resilient tongue-like parts integral therewith and spaced from said stop means suflicient- 1y to accommodate the thickness of said plate member therebetween for holding said transformer structure assembled to said plate.

6. A construction as claimed in claim 5 in which said stop means is in'the form of opposed flanges which respectively overlap said peripheral flanges of said end casing and are cut away for accommodating said opposed resilient tongue-like parts.

'7. In. apparatus of the character described, in combination, a transformer structure comprising a casing for housing the transformer core and winding, and a plate-like member for mechanical interconnection with said transformer, said plate member having an aperture therein, into which said transformer structure is receivable, said casing being made of sheet metal and comprising two end casing sections having peripheral flanges to rest respectively against two opposed side faces of said core for closing over the winding on the latter and means forming a third casing section extending along edge faces of said core with mechanical connection to opposed portions of said peripheral flanges to hold said end casing sections assembled to said core and providing stop means to limit the extent of passage of said transformer structure into said aperture with one of said two end casing sections entering the aperture foremost or with the other of said end casing sections entering said aperture foremost, said casing having opposed resilient tongue-like parts which are in two groups, being respectively extensions of said two end casing sections and being respectively spaced from said stop means sufficiently to accommodate the thickness of said plate member therebetween for holding said transformer structure assembled to said plate.

8. In apparatus of the character described, in combination, a transformer structure comprising a casing for housing the transformer core and winding, and a plate-like member for mechanical interconnection with said transformer, said plate member having an aperture therein, into which said transformer structure is receivable, said casing being made of sheet metal and comprising two end casing sections having peripheral flanges to rest respectively against two opposed side faces of said core for closing over the winding on the latter and means forming a third casing section extending along edge faces of said core with mechanical connection to opposed portions of said peripheral flanges to hold said end casing sections assembled to said core and providing stop means to limit the extent of passage of said transformer structure into said aperture with one of said two end casing sections entering the aperture foremost or with the other of said end casing sections entering said aperture foremost, said casing having opposed resilient tongue-like parts which are in two groups, being respectively extensions of said two end casing sections and being respectively spaced from said stop means sufficiently to accommodate the thickness of said plate member therebetween for holding said transformer structure assembled to said plate, at least two of said tongue-like extensions being in the form of leg-like standards and being capable of use for securing the transformer structure to a supporting surface or the like.

ROBERT S. EDWARDS. 

